Global Positioning Systems

1
Global Positioning Systems

• Presented by Wesley D. Fulbright

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What is GPS?

• A worldwide radio-navigation formed from a
  constellation of 24 satellites and ground
  stations
• These days GPS is finding its way into cars,
  boats, planes, construction equipment, movie
  making gear, farm machinery, even laptop
  computers.
• Used to calculate positions accurate to a couple
  of meters

3
How GPS Works

• Use satellites as reference points use 3
  satellites to triangulate position
• The GPS receiver measures distance by using the
  travel time of radio signals
• Timing is configured by using atomic clocks
• Using a 4th satellite ensures the perfect time
  if timing is off by a thousandth of a second it
  can mean almost 200 miles of error

4
Where are the Ground Stations

• Hawaii
• Ascension Island
• Diego Garcia
• Kwajalein
• Colorado Springs

5
Who uses GPS?

• Scientists
• Farmers
• Soldiers
• Pilots
• Surveyors
• Hikers

• Delivery Drivers
• Sailors
• Dispatchers
• Lumberjacks
• Fire Fighters

6
Types of Errors

• Passing through the different layers of the
  atmosphere slows the wave down
• Local obstructions on the ground
• Atomic clock errors
• Using satellites that are close together

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The End
Reference www.trimble.com